1. Field of the Invention
The present invention relates to fiber optic cordage useful as a fanout, a partial fanout, such as a jumper with one or more taps, or a jumper to reorder cores of a multi-core fiber (MCF). More particularly, the present invention relates a connector for such cordage, wherein the connector has several single core fibers arranged within a single holder of a ferrule, so as to mate with all, or several, cores of a MCF of a mating connector, such that the MCF is broken out into single core fibers, which can be more easily and conventionally manipulated.
2. Description of the Related Art
Optical network operators are continuing to look for ways to obtain increased density of optical fiber networks. One method for packaging higher numbers of light carrying paths in a small space is through the use of a MCF. A MCF typically comprises a central core surrounded by several satellite cores in a radial pattern surrounding the central core. Each of the central and satellite cores is potentially a light carrying path, and the MCF thus provides multiple parallel paths for optical signal transmission and/or reception in a single fiber.
A MCF is known in the existing arts. See for example, U.S. Pat. Nos. 5,734,773 and 6,154,594 and U.S. Published Applications 2011/0229085, 2011/0229086 and 2011/0274398, each of which is herein incorporated by reference. In the background art of U.S. Published Application 2011/0274398, as depicted in FIGS. 1 and 2, a MCF 180 has a central core 181 and multiple satellite cores 182, e.g., six satellite cores 182-1, 182-2, 182-3, 182-4, 182-5 and 182-6, in a common cladding layer 184. The satellite cores 182 are positioned around the central core 181 symmetrically, at the vertices of a regular hexagon 183.
Each of the central and satellite cores 181 and 182 exhibits a same diameter. The central core 181 and each of the satellite cores 182 has a diameter of about 26 micrometers (um), depicted as distance A in FIG. 2. A center to center spacing between adjacent central and satellite cores 181 and 182 is about 39 um, depicted as distance B in FIG. 2. Other dimensions and spacing, besides those shown in U.S. Published Application 2011/0274398, as depicted in FIGS. 1 and 2, are known in the background art. Also, more or fewer satellite cores 182 are known in the background art. Each of the central and satellite cores 181 and 182 may carry a unique light signal. Each MCF 180 is affixed within a ferrule and terminates at or near an end surface 245 of the ferrule. The ferrule may be part of a connector, which facilitates communicating the signals of the central and satellite cores 181 and 182 to a device via a port, or to further cabling via an adapter.
FIG. 3 depicts a typical connector 201 having a cylindrical ferrule 203 with a holder, e.g., a cylindrical central bore, presenting an end of a single MCF 180 for mating to another connector, via an adapter, or for communicating with a port of a device. FIG. 3A is a perspective view showing a ferrule assembly 232 within the connector 201, which extends along an axis 236. The ferrule assembly 232 includes the ferrule 203, a ferrule barrel 241 and tubing 242. The ferrule 203 has its holder formed as a precision hole extending down its length, along axis 236. The hole is shaped to closely receive a bare MCF 180 from a stripped end of an optical fiber cable 244. The bare MCF 180 is cleaved at the ferrule's end surface 245 and polished, resulting in an exposed fiber end face, as depicted in FIG. 2. Ferrule barrel 241 includes a hexagonal flange 246 and a front cone portion 249 having a pair of slots 247 in its perimeter. The structures of FIG. 3A are conventional and can be seen in US Patent Application Publication 2011/0229085.
FIG. 4 depicts an MT-type ferrule 303 having first and second holes 305 and 307 for accepting alignment pins of a mating ferrule. Between the first and second holes 305 and 307, the MT-type ferrule 303 presents an array of twelve fiber ends of MCFs 180-1 through 180-12 for communicating to MCFs of the mating ferrule. The fiber ends are located within holders, e.g., cylindrical channels, of the ferrule 303. An access window 309 opens to the MCFs 180-1 through 180-12 and can be used to flood epoxy into the v-grooves below the window 309 and/or the cylindrical channels, as is conventional in the art. US Patent Application Publication 2004/0189321, which is herein incorporated by reference, shows a typical MT ferrule.
Although FIG. 3 shows an LC type connector 201 and FIG. 4 shows a MT ferrule 303, which could be used in a MPO/MTP type connector, other connector styles for presenting a single MCF or multiple MCFs in an ordered array are known in the existing art, such as ST, SC and MT-RJ. Further the row of MCFs presented by the ferrule 303 may include more or fewer MCFs, such as eight or sixteen MCFs in one or two or more rows. Hereinafter, the term holder is broad enough to encompass all structures holding a fiber, such as v-grooves and channels with circular or other non-circular cross sectional shapes.
Fiber optic jumpers, patch cords, trunk cables, fanouts and other cable configurations provide optical connectivity in numerous spaces including local area networks (LANs), wide area networks (WANs), datacenters, vehicles, aircraft and ships. Historically, fanouts and jumpers have used one or more single-core optical fibers to mate with one or more single-core optical fibers presented by a termination. With the advent of the MCF, new fanouts and new jumpers are needed to deal with the multiple cores within a MCF.